Dozens of people are feared dead, including seven children, after a huge tornado ripped through an Oklahoma town destroying scores of homes and a primary school.

Initially 51 victims were been confirmed dead with estimates of another 40 bodies remaining to be found. But medical examiners later revised the toll to at least 24 dead and think some victims were counted twice.

The half-mile-wide tornado hit the Oklahoma City suburb of Moore in the US Midwest with winds of 200 mph. It smashed its way across the community of 41,000 for 45 minutes Homes were crushed into piles of broken wood. Cars and trucks were left crumpled on the roadside.

More than 120 people were being treated at hospitals, including about 50 children.

President Barack Obama declared a major disaster and ordered federal aid to supplement state and local recovery efforts. State governor Mary Fallin said the search for survivors went on, adding: "Hearts are broken" for parents looking for their children.

At Plaza Towers Elementary School, the storm tore off the roof, knocked down walls and turned the playground into a mass of twisted plastic and metal.Children from the school were among the dead, but several were pulled alive from the rubble. Rescue workers passed the survivors down a human chain. A man with a megaphone called out the names of surviving children. Parents waited nearby, hoping to hear their names.

As dusk began to fall, heavy equipment was rolled up to the school, and emergency workers crawled among the ruins. Because the ground was muddy, bulldozers and diggers were getting stuck. Men used jackhammers and sledgehammers to tear away concrete, and chunks were being thrown to the side as the workers dug.

Another school, Briarwood Elementary, was also damaged by the tornado, but not as extensively as Plaza Towers. The tornado also destroyed the city hospital and numerous businesses. Moore Mayor Glenn Lewis watched it pass through from his jewellery shop."All of my employees were in the vault," he said.

Mr Lewis, who was also the mayor of Moore when the strongest tornado on record whipped the city in 1999, said the most recent storm will not deter the community from rebuilding. In May 1999 a storm produced the highest winds ever recorded near the Earth's surface - 302 mph. It was the fourth tornado to hit Moore since 1998. A twister also struck in 2003.

The devastation in Oklahoma came almost exactly two years after an enormous twister ripped through the city of Joplin, Missouri, killing 158 people and injuring hundreds more.